Method for producing an FBGA component and substrate for carrying out the method

Abstract

A semiconductor component includes a substrate having a chip side and a solder ball side. A semiconductor chip is mounted on the chip side of a substrate. The semiconductor chip is electrically conductively connected to a conductor structure on the substrate. Ball pads are disposed over the solder ball side of the substrate. The ball pads are electrically conductively connected to the conductor structure and suitable for application of solder balls. A mask made from a soldering resist is disposed on the solder ball side. A sealing region at a surface of the solder ball side of the substrate is provided with seal elements for a sealing connection to an encapsulation mold on the surface of the solder ball side.

Description

[0001] This application claims priority to German Patent Application 10 2005 002 862.4, which was filed Jan. 20, 2005, and is incorporated herein by reference. TECHNICAL FIELD [0002] The invention relates to the field of semiconductor production. In particular, the invention relates to the enveloping of semiconductor chips after their mounting on a carrier substrate. BACKGROUND [0003] During the production of semiconductor components, semiconductor chips are mounted on substrates. In this case, it is also possible for a plurality of semiconductor chips to be mounted one above another. A substrate has a conductor structure serving for connecting the semiconductor chip to an external circuitry. The conductor structure comprises conductive tracks, contact pads and ball pads. [0004] FBGA housings (FBGA=Fine Ball Grid Array) are known for connecting the conductor structures to an external circuitry. In this case, the substrate has a chip side, on which the chip or the chip stack is mount...

AI Technical Summary

Benefits of technology

[0018] In one aspect the invention improves a sealing of the encapsulation mold for the lower housing part on the solder ball side with respect to the substrate surface thereof and in so doing reducing the risk of the substrate breaking and the production outlay on encapsulation molds and increasing the service lives thereof.

[0047] A further embodiment, which enables a seal independently of the elasticity of the soldering resist, consists in the fact that the substrate surface has a layer made of elastic material in the sealing region. In particular, the layer may be arranged as an elevation. The elevation makes it possible for the seal also to be able to yield laterally, thereby supporting the sealing effect.

Problems solved by technology

It has been shown in practice, however, that this is accomplished only inadequately.

This is disadvantageous particularly when molding the lower housing part on the solder ball side, since this escaping mold compound may also pass onto the solder balls or in the vicinity thereof and thus adversely influence later mounting processes, such as soldering-on.

This problem is exacerbated by the fact that in FBGA housings having a lower housing part, the conductor structure is quite generally arranged on the solder ball side.

As a result, leakages occur between the encapsulation mold and the substrate surface on the solder ball side since the surface is not even.

However, increasing the pressure force has the disadvantage that the substrate is exposed to a very high mechanical stress, which may result in the substrate breaking.

Such a configuration of encapsulation molds requires very small manufacturing tolerances, which leads to costly manufacture.

On the other hand, the service lives of the encapsulation molds are short since the slightest damage to the sealing web results in the encapsulation mold being unusable.

Finally, the problem of the substrate breaking is increased even further when the narrow webs are combined with increasing the pressure force.

This leads to a pressure force distribution that is as uniform as possible, but does not avoid the risk of the substrate breaking.

A flowability reduced in this way has the effect that it is more difficult for mold compound to emerge through leakages between the encapsulation mold and the surface on the solder ball side.

However, devising a mold compound of this type is associated with considerable costs.

Moreover, the lower flowability may give rise to problems during the molding process itself.

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